8 Replies Latest reply on Mar 19, 2014 2:38 PM by philip.nielsen

    Audio filter amplifyers

    philip.nielsen
              Hearing loss. Can I use the PSOC 1 to create a profile for my hearing loss   
        • 1. Re: Audio filter amplifyers
          user_1377889

          There are probably much better dedicated DSPs for audio-filtering than a PSoC1. The filter is not able to adapt frequency enhancement on several different freequencies as in hearing-aid devices.

             

          Supressing or enhancing a single frequency band as in a bandpass or in a bandstop can be done easily in PSoC1 with a PGA and a filter.

             

           

             

          Bob

          • 2. Re: Audio filter amplifyers
            user_14586677

            Years ago the peformance level of simple BP and BR filters was

               

            considered adequate at the 2'ond to 4'th order level. But if your

               

            hearing loss complex, not a simple smooth peak or reduction

               

            in response, those methods no longer considered adequate.

               

             

               

            Additionally you have to deal with switching noise in switch cap filters,

               

            which PSOC is, unless you use its PGA to synthesize continuous time

               

            filters. Not difficult to do, a simple LP filter gets rid of most of the noise

               

            due to oversampling nature of SC filters. But then you also have the

               

            same problem on the D/A side of a digitial filter.

               

             

               

            PSOC 1 can do digital filtering, it has an onboard multiplier, and you can

               

            implement IIR, or FIR, but not as wide a range of response as PSOC

               

            3/5.

               

             

               

                

               

                      

               

            http://www.cypress.com/?rID=2813     AN2099

               

             

               

             

               

            Regards, Dana.

            • 3. Re: Audio filter amplifyers
              philip.nielsen
                      Thanks for the feedback. What DSP IC do you think would be a fast learning rate. I can't see myself spending $4500 for hearing aids.   
              • 4. Re: Audio filter amplifyers
                user_14586677

                You could consider PSOC 3 or 5LP, as they both have DFB. As well as

                   

                basic signal conditioning like OpAmp, PGA. DFB also has assembler permitting

                   

                you to create custom filter.

                   

                 

                   

                One of your challenges will be size, package will be one of the issues.

                   

                 

                   

                Regards, Dana.

                • 5. Re: Audio filter amplifyers
                  philip.nielsen
                          Thanks for the response. PSOC has the filter wizard that I like using for audio. If I used the filter block in PSOC 5 where would I find the software routines for the custom filters?   
                  • 6. Re: Audio filter amplifyers
                    philip.nielsen
                            I am not concerned about size. I was thinking of a package size like an MP3 player.   
                    • 7. Re: Audio filter amplifyers
                      user_14586677

                      Custom filters are your ground up design by using the basic HW in the

                         

                      DFB. There are library sized collections of books on DSP filtering,

                         

                      many vendors have tools to determine pole/zero locations, show response

                         

                      you will get, just google "digital filter design tool".

                         

                       

                         

                      Regards, Dana.

                      • 8. Re: Audio filter amplifyers
                        philip.nielsen
                                I purchased the EVAL-ADAU1452MINIZ. The SDK was $225. It comes with GUI software. I still think the PSOC 5LP is the way to go.